An optical spectrometer is a device that can analyze the incoming light by frequency (wavelength) components and their intensities. In general, there are two types of spectrometers: dispersive and interferometric. A dispersive spectrometer has an optically dispersive component (e.g. prism or grating) to spatially disperse the incoming light as a function of wavelength. The dispersed light is collected by multi-channel detectors. An interferometric spectrometer records the interference pattern generated by the incoming light, and mathematically converts the interference pattern to a spectrum. An example of an interferometric spectrometer is a Fourier-transform infrared spectrometer (FTIR) based on a Michelson interferometer (FIG. 1).
The current spectrometers have two limitations for use in home and field applications such as for medical diagnosis. First, the size of the spectrometer (spectrometer as a component of a spectroscopy system) is too big. Typical spectrometers are bench-top models. Even the “portable” spectroscopic systems are toolbox or briefcase size. Thus, the current spectrometers are too big to be used in field applications or at home environment. Second, the cost of typical spectroscopy systems is more than $100,000. Thus, there is a need for a miniaturized, preferably hand-held approximately palm-size, spectrometers.